Item 45: Use member function templates to accept “all compatible types.”

Smart pointers are objects that act much like pointers but add functionality pointers don't provide. For example, Item 13 explains how the standard auto_ptr and tr1::shared_ptr can be used to automatically delete heap-based resources at the right time. Iterators into STL containers are almost always smart pointers; certainly you couldn't expect to move a built-in pointer from one node in a linked list to the next by using “++,” yet that works for list::iterators.